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The first diagnosed cases of Phenylketonuria (PKU) were identified in 1934 by Norwegian doctor Asbjorn Folling. Dr. Folling found that the urine of two of his young mentally handicapped patients contained a high level of phenylalanine. Follwing this discovery, it was found that the absence or malfunction of the phenylalanine hydroxylase enzyme is due to the mutation of the ''PAH'' gene and inherited autosomal recessively. This may result in a genetic disorder known as Phenylketonuria (PKU). This information was not utilized until the early 1950s when it was found that under a low phenylalanine diet, some of the symptoms found in children suffering from PKU could be reversed. Due to a diet rich in phenylalanine, this enzyme is vital in the regulation in phenylalanine plasma concentration by converting about 75% of the amino acid to tyrosine. Excessive amounts of phenylalanine has been shown to cause mental retardation in humans. Presently, it is regulation to screen newborns children for phenylketonuria with a simple blood or urine test. <ref> January 2005: Phenylalanine Hydroxylase [http://www.pdb.org/pdb/education_discussion/molecule_of_the_month/download/PhenylalanineHydroxylase.pdf]</ref> | The first diagnosed cases of Phenylketonuria (PKU) were identified in 1934 by Norwegian doctor Asbjorn Folling. Dr. Folling found that the urine of two of his young mentally handicapped patients contained a high level of phenylalanine. Follwing this discovery, it was found that the absence or malfunction of the phenylalanine hydroxylase enzyme is due to the mutation of the ''PAH'' gene and inherited autosomal recessively. This may result in a genetic disorder known as Phenylketonuria (PKU). This information was not utilized until the early 1950s when it was found that under a low phenylalanine diet, some of the symptoms found in children suffering from PKU could be reversed. Due to a diet rich in phenylalanine, this enzyme is vital in the regulation in phenylalanine plasma concentration by converting about 75% of the amino acid to tyrosine. Excessive amounts of phenylalanine has been shown to cause mental retardation in humans. Presently, it is regulation to screen newborns children for phenylketonuria with a simple blood or urine test. <ref> January 2005: Phenylalanine Hydroxylase [http://www.pdb.org/pdb/education_discussion/molecule_of_the_month/download/PhenylalanineHydroxylase.pdf]</ref> | ||
==== Symptoms ==== | |||
Phenylalanine plays a variety of roles in the body among which is the production of melanin, the pigment responsible for hair and and skin color. Infants with an over abundance of this residue may therefore have a lighter skin, hair and eye color than those who do not. | |||
Other symptoms may include: | |||
- Delayed mental and social skills | |||
- Head size significantly below normal | |||
- Hyperactivity | |||
- Jerking movements of the arms or legs | |||
- Mental retardation | |||
- Seizures | |||
- Skin rashes | |||
- Tremors | |||
- Unusual positioning of hands | |||
==== Treatment ==== | |||
=== Treatment === | |||
Treatment for such a PKU is a low phenylalanine diet and early detection. Those who start the diet early and adhere to it will have better mental and physical health. Infants diagnosed with the disease can fed a specially made formula called Lofenalac while others should follow a diet plan as illustrated in the image to the left. The main rule to follow is to avoid protein sources rich in phenylalanine and sugars containing aspartame. Taking extra supplements like fish oil can replace the fatty acids missing from the phenylalanine free diet and may also improve neurological development. PKU can also be caused by a deficiency in or inability to regenerate tetrahydrobipternin, the cofactor essential to the function of PheOH. Although this is not usually the cause of PKU, patients can be treated by taking tetrahydrobiopterin supplements. <ref> A.D.A.M Medical Encyclopedia, Phenylketonuria. [http://http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002150/]</ref> | Treatment for such a PKU is a low phenylalanine diet and early detection. Those who start the diet early and adhere to it will have better mental and physical health. Infants diagnosed with the disease can fed a specially made formula called Lofenalac while others should follow a diet plan as illustrated in the image to the left. The main rule to follow is to avoid protein sources rich in phenylalanine and sugars containing aspartame. Taking extra supplements like fish oil can replace the fatty acids missing from the phenylalanine free diet and may also improve neurological development. PKU can also be caused by a deficiency in or inability to regenerate tetrahydrobipternin, the cofactor essential to the function of PheOH. Although this is not usually the cause of PKU, patients can be treated by taking tetrahydrobiopterin supplements. <ref> A.D.A.M Medical Encyclopedia, Phenylketonuria. [http://http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002150/]</ref> | ||
